It was common for master cylinders to be manufactured by being cast or molded from a common metal such as cast iron and thereafter an axial bore and associated compensation ports brought into a desired specification by a machining operation. In order to reduce the weight of a master cylinder the cast iron was replaced with aluminum and still later only the body made of aluminum while the reservoir was made of a plastic material. U.S. Pat. Nos. 4,514,983 and 5,743,092 disclose an attachment arrangement for securing such a plastic reservoir to a metal housing through the use of engaging tabs whereas U.S. Pat. Nos. 5,647,212 and 5,743,093 disclose a more positive attachment through a projection on the reservoir which is bolted to the housing of the master cylinder. These attachment arrangements perform in a satisfactory manner. Unfortunately, considerable material is required for the projections and they are often located in a position where damage may occur or manufacturing tolerances may introduce side loading forces on seals associated with the connection such that a leak path may occur.